首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   44296篇
  免费   2586篇
  国内免费   129篇
耳鼻咽喉   354篇
儿科学   1303篇
妇产科学   1410篇
基础医学   6315篇
口腔科学   935篇
临床医学   5285篇
内科学   8347篇
皮肤病学   847篇
神经病学   4667篇
特种医学   1541篇
外国民族医学   3篇
外科学   4755篇
综合类   304篇
一般理论   64篇
预防医学   4176篇
眼科学   667篇
药学   3050篇
  1篇
中国医学   81篇
肿瘤学   2906篇
  2023年   275篇
  2022年   512篇
  2021年   923篇
  2020年   621篇
  2019年   858篇
  2018年   1082篇
  2017年   769篇
  2016年   880篇
  2015年   1085篇
  2014年   1363篇
  2013年   2033篇
  2012年   2917篇
  2011年   3116篇
  2010年   1609篇
  2009年   1549篇
  2008年   2473篇
  2007年   2643篇
  2006年   2694篇
  2005年   2454篇
  2004年   2289篇
  2003年   2205篇
  2002年   1982篇
  2001年   836篇
  2000年   824篇
  1999年   671篇
  1998年   476篇
  1997年   387篇
  1996年   292篇
  1995年   254篇
  1994年   231篇
  1993年   254篇
  1992年   427篇
  1991年   400篇
  1990年   415篇
  1989年   408篇
  1988年   343篇
  1987年   352篇
  1986年   329篇
  1985年   306篇
  1984年   244篇
  1983年   237篇
  1982年   180篇
  1981年   158篇
  1979年   237篇
  1978年   144篇
  1977年   144篇
  1975年   181篇
  1974年   195篇
  1973年   161篇
  1972年   164篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  相似文献   
3.
4.
5.
6.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
7.

Background

One approach to boost influenza vaccination coverage has been to expand immunization authority. In 2012, the province of Ontario gave community pharmacists the authority to administer the influenza vaccine.

Objective

This study investigates the perspectives of Ontario pharmacy patrons, who had not recently received this vaccine from a pharmacist, regarding this pharmacist service.

Methods

A survey was administered in six Ontario community pharmacies to pharmacy patrons who had not received an influenza vaccination from a pharmacist during the previous year. The instrument included questions about influenza vaccination, and knowledge of and attitudes toward vaccines and pharmacist-administered immunization.

Results

A total of 541 pharmacy patrons completed the survey (53.9% response rate). About one-third (30.5%) of respondents were not aware that pharmacists could give the influenza vaccine, with younger individuals being less likely to be aware (OR 0.48, 95% CI 0.29–0.77, p?<?0.05) and less likely to receive the vaccine annually (OR 0.28, 95% CI 0.19–0.42, p?<?0.05). Leading reasons respondents gave as to why they did not receive their influenza vaccine from a pharmacist included not wanting or feeling they needed to be immunized (41.6%) and being used to receiving the vaccine from a physician (16.5%). Concerns about the experience and training of pharmacists and lack of privacy in a community pharmacy were uncommon.

Conclusion

Reduced awareness of the availability of pharmacist-provided influenza vaccine is still common. Pharmacists have a significant opportunity to address lack of awareness and vaccine hesitancy issues. They can promote this service to increase influenza vaccination rates among pharmacy patrons who do not utilize this professional service.  相似文献   
8.
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号